Hepatitis C virus (HCV) is an important cause of chronic liver disease worldwide. In some areas the prevalence of hepatitis C is extremely high, as in Egypt, Saudi Arabia, the Phillipines and Papua New Guinea. The prevalence of hepatitis C antibody in volunteer blood donors is generally estimated at between 0.4% and 1%.
HCV has been described as the "shadow epidemic" because of the insidious nature of the infection which is generally asymptomatic and persists for life in 85% of patients infected with the virus.
HCV has tremendous genetic diversity and this enables it to escape the surveillance of the immune system of infected individual thus leading to chronic infection. In the same light, there are difficulties in vaccine development.
HCV is largely transmitted parenterally, i.e. by blood and blood products. Therefore, HCV infections may be acquired via the following means:
The onset of infection is often unrecognised and the early course is generally indolent. The natural history of HCV infection is dependant upon on geography, alcohol use, viral characteristics ( different genetic types, viral load ), co-infection with other viruses and some as yet unidentified factors.
After exposure to the virus, detectable viral genetic material called HCV RNA is seen in the blood in 1 - 3 weeks. Nearly all patients show evidence of liver injury because blood tests for liver enzymes become elevated. However, only 25% patients manifest symptoms like lassitude, anorexia and some became jaundiced (yellowing of eyes and skin). Rapid progression to liver failure due to fulminant hepatitis is a rare occurrence.
The majority of patients (85%) fail to clear the virus within 6 months and develop chronic hepatitis C. These patients are relatively well in the first 2 decades after acquiring the infection. However in 20% of these carriers, there may be intermittent symptoms of fatigue and malaise.
